Abstract
Aim: To study the
disease incidence and diversity of Begomovirus infection and crop loss
due to spread of virus across different districts of North Bengal.
Methodology:
Several
fields in different districts of North Bengal were surveyed and potential
begomoviral-infected samples were collected for further analysis. Total DNA
extraction, PCR analysis, sequencing and phylogenetic analysis were
conducted.
Results:
During
2019-2021, ten fields of each district were surveyed and begomoviral
occurrence was observed in almost every field. The disease incidence in
different districts varied from 15-45%. The highest disease (42.5%) incidence
of was observed in the Darjeeling district while the lowest (15%) was
recorded from Alipurduar district. The maximum crop loss due to Begomovirus
was 64-100% in bitter gourd, 40-80% in cucumber and 20-30% in wax gourd. 153
samples from 6 different cucurbits were collected and analysed. PCR using
AV494/AC1048 primers that amplified coat protein region (~550bp) showed 74%
of the samples as positive. Upon sequencing and BLAST analysis, ToLCNDV,
SLCCV and BGYVV were detected. In phylogenetic analysis, the isolates
clustered in three separate clades based on Begomovirus species
irrespective of the hosts. Present isolates showed more closeness to Indian
and Bangladesh isolates.
Interpretation:
The
documentation of disease severity caused by Begomovirus is of extreme
importance for food security of the people. Present study revealed that Begomovirus
is present in all the crop field studied. The results indicated an urgent
need for the management of the viruses to save crops.
Key
words: Begomovirus, Cucurbitaceous
crops, Disease incidence, North Bengal
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